Lubricant



turallformula:

Patented Oct. 30, 1945 UNITED STA; E s PATENT 2,388,058 QFF ICE.

2,388,058 LUBRIOANT of Maine :No Drawing. Application April 24, 1943, Serial No. 484,470

7 Claims. (CI. 25.2-51.5)

This invention I relates to an improved turbine oil. It'relate zmore particularly to a lubricating w oil composition consisting principally of a pctroleum lubricatingoil, the characteristics of the 011 being modified by the addition thereto of a relativelysmall proportion of "a diaminomethane derivativeof the class represented by the strucwhere RiN is a nitrogen-containing heterocyclic radical, R2 is either hydrogen or an alkyl or an aryl radical, R: and R4 are alkyl or aryl radicals V structural formula:

CHz-CH:

X\ CHPC:

where X, for instance, is oxygen, as in the morpholino radical, or is an alkyl radical, for instance CH2, as in the piperidino radical.

A lubricating oil composition to be used as a turbine oil, and especially in modern marine steam turbines, is subject to very exacting requirements. Not only must it perform the ordinary function of lubricating the turbine over prolonged periods without interruption but usually it must serve as a coolant, to lubricate the gearing mechanism, to operate oil-actuated governors or control mechanisms having very nice tolerances and lubricate other auxiliary equipment.

Many lubricating oil compositions highly satisfactory for the lubrication of other mechanisms have been found wholly unsuitable for use as a turbine oil. Thi is probably due primarily to the fact that in normal use turbine oils rapidly become-contaminated with water. Whatever the cause, it is generally recognized that the performance of a turbine oil is not predictable from consults of such rusting not only interfere with the operation of and tend to clog the delicate clearwith resultant sludge formation which may further aggravate such conditions. The products of such rustingalso appear to act as emulsifying agents.

ances of the oil system but the products of the rusting appear to catalyze oxidation of the oil We have discovered that the previously experienced rusting of metal parts within the oil sys tem in steam turbines may be. substantially inhibited by incorporating in the oil a minor proportion of a diaminomethane derivative of the class previously identified herein. Compounds of this class found to be especially effective inJinhibitin rusting under conditions usually encountered by turbine oils are those in which the nitrogen-containing heterocyclic radical or radicals is of the class consisting of-morpholinoand piperidino radicals.

such compounds found to be especially efiective in the preparation of our improved turbine oils of the present invention may be exemplified by the following:

Dimorpholino-metha'ne, which we believe to be represented by the structural formula Dipiperidino-methane, which we believe to be represented by the structural formula- Diethylamino-morph0linomethane, which we believe to be represented by the structural formula- CHr-CHa 2 l o N--CHa-N CHr-Cfi2 C2115 Phenyl dimorpholinomethane and phenyl dipiperidinomethane, which we believe to be represented "by the structural formula where R2 is a phenyl radical and X is, respectively, O and CH2.

l i l 1 J l l 1 i l It will be understood that the foregoing specific compounds are illustrative of the'class and that our invention is not limited to the use of these particular compounds but contemplates the use of other members of the class in the compounding of our improved turbine oils.

Many of the compounds suitable. for use in compounding our improved turbine oil are known to the art and may be readily prepared by known methods. In general they can be produced'as condensation products of amines and aldehydes.

For example, the dimorpholinomethane referred to herein and in the appended claims was prepared as follows: There was placed in a 250 c. c. Erlenmeyer flask 95.7 grams (1.1 moles) of morpholine. To this there was added portionwise with shaking 43 grams of 35% to 40% formalin (0.50-0.57 mole formaldehyde). During this addition, considerable heat was evolved. The solution was then allowed to stand at room temperature for 2 to 3 days and was then subjected to distillation for the separation of water and any unreacted morpholine and formaldehyde and volatile reaction products present. There resulted a yield of 96 grams of the dimorpholinomethane which was equivalent to 93.8% of the theoretical yield. This product was a waterwhite liquid boiling at 165 to 177 F. at an absolute pressure of 0.5 mm. of mercury and was found by analysis to contain 14.8% of nitrogen as compared with the theoretical nitrogen content of about 15% for pure'dimorpholinomethane.

In a second preparation of the dimorpholinomethane, 539.4 grams (6.2 moles) of morpholine was placed in a 1-liter, B-necked flask and, to this, 265 grams of 34%-37% formalin (about 3 moles of formaldehyde) was added portionwise over a; period of 20 minutes with shaking and sufiicient cooling to keep the temperature of the mixture below 150 F. The resulting solution was heated for 2 hours using a reflux condenser to return volatile material to the flask and was finally distilled, 5 outs being taken. The amount of each cut and the condition under which it was taken were as follows:

Pressure mm. Amount of Out Overhead temperature of mercury out 1.- 167-215" F Atmospher- 224 c. c.

2. 205210 F. 6 grams.

3. 210-215 F. 550 grams. 4 215-220 F. 6.6 grams. 5 Residue 6 gram The third cut was found by analysis to contain 14.8% of nitrogen and, at 20 C., to have a specific gravity of 1.0494 and a refractive index of 1.4803. Its molecular refraction was 50.46 as compared with the theoretical molecular refraction of 50.53 for pure dimorpholinomethane.

. The yield of this fraction was 95.4% of the'theo- An analysis of the aqueous overhead indicated the presence of 3% to 5% of nitrogen compounds.

The dipiperidinomethane, referred to herein, prepared as follows: 91.5 grams of 93% piperidine (1 mole) was placed in a 250 c. c. Erlenmeyer flask. To this there was added portionwise with shaking over a period of 15 minutes grams of 34% formalin (0.5 mole formaldehyde). Durin this addition, considerable heat was evolved and the temperature of the mixture increased to about 170 F. Before the addition of the formalin solution was completed, two phases formed in the flask, a lower aqueous phase and an upper organic phase. The lower phase was separated and on salting out with potassium carbonate yielded 2 c, c. of a red liquid. The upper organic phase was distilled, four cuts being taken. The conditions under which the cuts were taken and the amounts thereof were as follows:

The second out was found by analysis, b the Dumas Method, to contain 15% nitrogen as compared With the theoretical nitrogen content of 15.38% for pure dipiperidinomethane. At 20 C. it had a specific gravity of 0.9269 and a refractive index of 1.4886. This second. cut was equivalent to 81.6% of the theoretical yield. The aver-' age molecular refraction of several batches of the product thus prepared was found to be 56.57 as against a theoretical molecular refraction of 56.48

for pure dipiperidinomethane.

The residue, out four, was a viscous, dark red liquid.

The diethylamino-morpholinomethane referred to herein and in the appended claims was prepared as follows: 281 grams of 36.8% formalin (3.45 moles formaldehyde) was placed in a flask and there was added thereto portionwise over a period of 1% hours, with cooling and shaking, 261 grams (3 moles) of morpholine. This mixture was allowed to stand for four days and thereafter 343 grams of wet organic matter, morpholinomethanol, was salted out from the solution with potassium carbonate. 117 grams (1 mole) of the resultant morpholinomethanol was added portionwise with cooling over a period of 15 minutes to 76.7 grams (1.05 moles) of diethylamine in a 500 c. c. Erlenmeyer flask. Thereafter 10 grams of sodium carbonate was added, a reflux condenser fitted to the flask and the reaction mixture heated at F. for 4 hours. Some of the sodium carbonate dissolved in water present to form two liquid phases, an aqueous layer and an organic layer. The organic layer was separated from the aqueous layer and there was separated from the former, 'by distillation, 48 grams r an aces-,oss:

ofthe. diethylamino-morpholinomethane as a colorless; liquid. boiling within the range of 155-165 F., at: an absolute pressure of 3.5 to 3.0 millimeters; of: mercury and found by analysis to. contain 16.1% of nitrogen as compared with the theoretical nitrogen content of 16.3% for pure diethylamino-morpholinomethane. This yield was equivalent to 27% of the theoretical yield.

The dimorpholinoethane referred to herein and in the appended claims was prepared as follows: 174 grams (2 moles) of morpholine was placed in a -liter, S-necked flask equipped with a stirrer, and 20 grams of anhydrous potassium carbonate was added and suspended therein by stirring. 44 grams of acetaldehyde (1 mole) was then added to. the suspension over a period of 1% hours with stirring, the temperature being maintained at about 42 F. during most of this period. Stirring was continued for A.; hour and the mixture then allowed to stand over night. The resultant yellow liquid was then filtered and vacuum distilled. In this distillation the reaction products were heated to a temperature of, 185 F. at an. absolute pressure of 5 to millimeters of mercury to remove all unreacted morpholine and thereafter a cut was obtained Within a boiling range of 110 to 130 F. at an absolute pressure of 1.9 to 1.3 millimeters of mercury. By analysis, this cutv was. found to contain 13.7% nitrogen as compared with. the theoretical nitrogen content of 14% for pure dimorpholinoethane.

Thedipiperidinoethane referred to herein was prepared as follows: 179 grams of 95% pure .piperidine (2 moles) was placed in a 3-necked flask, equipped with a. stirrer, and there was addedthereto" 30. grams of anhydrous potassium carbonate. To this mixture there was added 48.4

grams (1.1 mole) of acetaldehyde over a period oi. 2 hours, with stirring, the mixture being kept at. a temperature below 55 F. during the addil tion by cooling. The reaction mixture was allowed to-stand over night and the aqueous potassium carbonate layer removed. The organic layer colored liquid.

The phenyl dimorpholinomethane referred to herein. and in the. appended claims was prepared as. follows: 91.3 grams. of morpholine (1.05 moles) was placed in a 250 c. c. Erlenmeyer flask. There was added thereto portionwise, with shaking, over a period of. 10 minutes, 53 grams (0.5 mole) of benzaldehyde. During this addition the temperature ofv the mixture rose to about 210 F. and globules of Water were formed. The reaction mixture became cloudy and solidified. 95 grams of the phenyl dimorpholinomethane was obtained as a white solid having a melting point of 214-216 F. and found by analysis to contain 10.6% of nitrogen as compared with the theoretical nitrogen content of 10.7% for pure phenyl dimorpholinomethane.

The phenyl dipiperidinomethane referred to herein was prepared as follows: 134.2 grams of 95% pure piperidine (1.5 moles) was placed in 1 a 500 c. c. Erlenmeyerflask and there was added thereto portionwise, over a period of 10 minutes with shaking, 79.5 grams (0.75 mole) of benzaldehyde. During this addition to temperature of the mixture rose to about 185 F. The solution clouded but, before permitting it to solidify, 300 c. c. of hot. ethyl alcohol was added. Upon coolas; 5 ear aww ing this mixture there was obtained 159 grams of phenyl dipiperidinomethane as a white solid having a melting point of 176 to 178 F. From the mother liquor and wash liquors. therewas obtained 15 additional. grams of the product.

In referring. to dimorpholinomethane, dipiper-- id-inomethane, diethylamino-morpholinomethane, dimorpholinoethane, dipiperidinoethane, phenyldimorpholinomethane and phenyl dipiperidinomethane herein and, in the appended claims, we refer, respectively, to the above-described products, although, of course, we intend to refer by these terms to the. same materials by Whatever process, they may be made- It is understood that our invention is not predicated upon the identification of the addends as. a matter of terminology.

The lubricating oil constituent of our improved turbine oil may consist of a petroleum lubricating fraction such as, ordinarily specified for turbine oils. It may with advantage be a highly refined lubricating oil, for instance an acidtreated petroleum lubricating oil fraction or one which has been subjected to solvent refining such as a phenol-treated fraction from East Texas crude. Solvent refined oils have generally been found more resistant to sludging than the acidtreated oils. For example, lubricating oils. such as a phenol-treated East Texas neutral (Sample I), and an acid treated fraction fromv a, Mich Continent crude (Sample II) having the following characteristics have been used with advantage:

Sample I Sample II Gravity, A. P. I 26. 7 23.1 Flash, F 405 440 Fire, F'. 455 515 Viscosity at l00-F., S. U. S- 227 483. 5 Viscosity at 210 F., S. U. S..- 46. B 56.1 Viscosity index (Dean and Ba 79 Pour, F +15 -10 Neutralization number 0. 025 0. 025- Saponification number 0. 28 0. 13 Carbon residue (Gonradson), per 0. 05' 0. 038 Ash, percent 0.003 0. 000 Sulfur, percent 0. 30 0. 47 Navy emulsion tests: v

Distilled water 0. la. 0. K. 1% salt solution 0. 1C. O. K. 1.0 N caustic solutio O. K./13 0. K./l5 Emulsiiying constitutents with steam. None None The Navy emulsion tests appearing in the fore- I Fuels, General Specifications (Methods for Sampling and Testing), VV-L-791a (October 2', 1934), Method 320.12.

By incorporating a minor proportion of a compound of the previously identified class in a suitable lubricating oil constituent, rusting of the metal parts within the oil system of the turbine may be materially inhibited. Depending upon the severity of the rusting conditions encountered. in service, including temperature, access of. air or other oxidizing gases to the oil, amount of water in contact with the oil, and the like, the proportion of the addend used may with advantage be varied from about 0.01% to about 1% by weight of the oil.

For example, with but one exception, the incorporation of 0.05% of any one of the compounds specifically described herein has been found to result in a clean test specimen or but a trace of rustin thereof when the turbine oil sions under conditions of use.

v American Society of Testing Materials and designated, respectively, A. S. T. M. Specification D-665-42-T for Turbine Oils and Proposed Method for Determining Oxidation Characteristics of Turbine Oils, Section III, Technical Comrlnifiee C, A. S. T. M. Committee D-Z, July 2,

A further essential characteristic of turbine oils is that they do not form objectionable emul- Consequently, in the compounding of such oils, it is necessary to y avoid the use of addends which might deleteriously affect the emulsifiability of the oil. A notable advantage of our improved turbine oil is that the emulsifying characteristics of the base oil are not adversely affected by the addends of the present invention.

While the compounds previously identified herein and used in the compounding of our improved turbine oils are not effective, when used alone, in preventing oxidation'of the oil under conditions of the prescribed turbine oil oxidation test'and, in fact, appear to be pro-oxidants under such conditions, they are compatible with known anti-oxidants, for example bis-(p-dimethylaminophenyl)-methane which may with advantage be used in conjunction therewith in our improved turbine oils-in order to combine high oxidation resistance with the anti-rusting characteristics of our turbine oils.

In the compounding of ourimproved turbine oil, a small amount of one of the above-identifled addends is admixed with a suitable petroleum lubricating oil in the conventional manner of compounding similar oil compositions. In addition to the lubricating oil constituent and the addend previously described, various other addition agents having the ability favorably to influence the characteristics of the turbine oil may be incorporated in the improved turbine oil of our present invention further to improve the properties thereof in various respects. The previously noted bis-(p-dimethylaminophenyl)- methane has been used with special advantage further to improve our turbine oil with respect to its oxidation characteristics.

The following examples of turbine oils, and their characteristics with respect to rusting, will serve as specific illustrations of the application of our invention with respect to various addends of the clas herein contemplated. Their characteristics with respect to rusting were determined by the previously referred to prescribed method for testing turbine oils. The results of these rusting tests are reported, as is customarily done, in terms of the amount of rusting of the test specimen, the letters A, B, C, D and E having the following significance:

I JUOW The rusting characteristics of our improved turbine oils having the indicated composition and in which the mineral oil constituent was that previously identified as Sample I were found to be as follows:

' Busting Addend con- Addend charactercentration istics Percent None E Dimorpholinomethane 0. 02 B Do 0.05 A 0. 10 A 0.20 A 0.06 B++ 0.10 A 0.20 A 0.50 A 0. 02 B++ 0.05 A 0.10 A 0.20 A 0.02 0 0.05 A 0.20 A 0.02 A 0. 05 A 0.20 A 0.02 B 0.05 A 3'5 131+ 0.5 B++ As appears from the results of these tests,

though the use of the oil constituent alone resulted in the rusting of 75% to 1.00% of the surface of the test specimen, the addition of as small an amount as 0.05% of any one of these addends, except the latter, afiorded complete or substantially complete protection against rusting and,'in many instances, only a, trace of rusting resulted where even smaller proportions of the addend were used.

In conducting these tests, turbine oils were prepared by compounding with the oil constituent dimorpholinomethane resulting from each of the eight preparations thereof previously described herein and the rusting characteristics were found to be substantially identical in each case.

The oxidation induction period of the oil designated Sample I was 150 hours and that designated Sample II was 250 hours. The inclusion of 0.2% of bis-(p-dimethylaminophenyl) -methane in our improved turbine oil resulted in increasing the oxidation induction period of the turbine oil to as high as 825 hours when Sample I oil was used and to as high as 960 hours when Sample II wasused. Further, by this inclusion, the rusting characteristics of our turbine oil were only slightly affected as shown by the following table:

We have found that by the use of relatively small proportions of bis-(p-dimethylaminophenyl) -methane in conjunction with one of the diaminomethane derivatives previously identiiied, the anti-rusting life of the turbine oil is actually considerably increased. A turbine oil excess of 1% comprising Sample I as the oil constituent, with 10.2% of dimorpholinomethane, was oxidized under the conditions of the oxidation test previously referred to. One portion, oxidized for 24 hours,

gave complete protection against rusting when tested by the' A. S. T. M. procedure. Another 1 portion, oxidized for 48 hours, did not give com- 'plete protection against rusting. Portions of the same oil containing 0.2% dimorpholinomethane and 0.2% bis (p dimethylaminophenyD-methane were oxidized for 72, 192, 384, and'960 hours. These oxidized portions, when tested by the A. S. T. M. procedure, gave comtion of the addend from ,the oil or substantial deterioration of the addend itself.

As previously indicated, depending upon conditions of use, the 'addend may with advantage be used in proportions ranging from about 0.01% to 1% by weight of the oil. Proportions even in may be used but such larger proportions have not been found necessary. Though proportions less than 0.01% may be used, such smaller proportions are usually not sufliciently efiective. Accordingly, proportions ranging from about 0.01% to about 1% are generally recommended.

In our application Serial No. 434,471, filed concurrently herewith, we have specifically claimed turbine oils comprising a diaminomethane derivative wherein at least one of the nitrogen atoms is included in a piperidino radical.

We claim:

1. An improved turbine oil which comprises a petroleum lubricating oil containing a proportion, effective to retard rusting, of a diaminomethane derivative of the class represented by the structural formula where RiN- is a nitrogen-containing heterocyclic radical, R2 is selected from the class consisting of hydrogen, alkyl and aryl radicals, and NR3R4 is a radical selected from the class consisting of nitrogen-containing heterocyclic radicals and radlicals wherein R3 and R4 are either alkyl or ary 2. An improved turbine oil which comprises a petroleum lubricating oil containing from about 0.01% to about 1% of a diaminomethane derivaa so. nuuwa wish in 2,388,058 5 tive of the class represented by the structural formula R1N('3H-N/ Ra R: where RIN is a morpholino radical, R2 is selected from the class consisting of hydrogen, alkyl and aryl radicals and NR3R4 is a radical selected from the class consisting of nitrogen-containing heterocyclic radicals and nitrogen-containing radicals wherein R3 and R4 are either alkyl or' aryl.

4. An improved turbine oil which comprises a petroleum lubricating oil containing from about 0.01% to about 1% of a diaminomethane derivative of the class represented by the structural formula where R1N is a nitrogen-containing heterocyclic radical, R2 is selected from the class consisting of hydrogen, alkyl and aryl radicals, and NR3R4 is a radical selected from the class consisting of nitrogen-containing heterocyclic radicals and nitrogen-containing radicals wherein R3 and R4 are either alkyl or aryl.

5. An improved turbine oil which comprises a petroleum lubricating oil containing from about 0.05% to about 1% of dimorpholinomethane.

6. An improved turbine oil which comprises a petroleum lubricating oil containing from about 0.05% to about 1% of 1,1-dimorpholinoethane.

'7. An improved turbine oil which comprises a petroleum lubricating oil containing from about 0.05% to about 1% of phenyl dimorpholinomethane.

ROBERT D. HERLOCKER. MILTON PAUL KLEINHOLZ. FRANKLIN M. WATKINS.

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